Effect of Warm Rolling Temperature on the Microstructure and Texture of Microcarbon Dual-Phase (DP) Steel

Abstract

The effect of warm rolling temperature on microstructure and texture of microcarbon dual-phase (DP) steel was investigated through scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The results showed that with the increase of rolling temperature, the density and thickness of the deformation band first increased and then decreased. Ferrite and fine martensite were observed in the annealed sheet, and the ferrite had a much more homogeneous distribution in the sample rolled at 450 °C. During warm rolling, the ferrite developed a dominant γ-fiber and a weak α-texture. During the annealing of the rolled sheet, the intensity of the γ-fiber was increased and a weak {001}<100> texture developed in the sample rolled at room temperature. An increase in the rolling temperature generated an initial decrease and subsequent increase in the strength of the unfavorable {001}<110> texture in the annealed sheet. In addition, the strength reached a maximum at 550 °C due to an increase in the dissolved carbon in the matrix, which was result of carbide dissolution. By contrast, the intensity of the γ-fiber remained relatively higher and was deemed the weaker {001}<110> component in the annealed sheet rolled at 450 °C. Therefore, a larger texture factor (fγ-fiber/f(α-fiber+λ-fiber)) can be produced under this process.